There are two goals for this project, (1) to study the relation between body temperature and crying in hyperthermic infants using an animal model, and (2) to expose undergraduate students to the procedures of research, so they can see beyond the list of steps they have memorized as the scientific method. Hypothermia can be a serious health problem for infants from poor families. Crying may help to warm cooling infants, but this has not been tested. This project will examine the role of crying and its metabolic cost, using neonatal rodents. The hypotheses to be tested are (1)that crying helps to warm hypothermic infants, and (2) that crying is a metabolically expensive way to produce heat, using more energy than other methods of thermogenesis. The procedure will be to measure body temperature and rates of crying and oxygen consumption in neonatal voles (field mice), Microtus ochrogaster, cooled in a metabolism chamber at 20 and 25oC for 30 minutes. Infant voles cannot keep their bodies warm in the first 10-14 days of life, and when isolated and cooled by produce loud, discrete ultrasonic cries. Individuals vary considerably in rate of crying, with some not even crying at all, so it will be possible to compare those that cry at high rates with those that do not cry. It is predicted that crying neonates will stay warmer than non-crying ones, but that it will be at considerable metabolic expense. That is, that crying is an expensive way to keep warm, and it is more efficient to produce heat by standard thermogenesis than by crying. Undergraduate students will participate in all aspects of the project, helping with the experiments and data analysis, and they will present the results at MBRS conferences. They will be able to see how hypotheses lead to predictions and then to experiments, results, and conclusions. They will also see that animal research can lead to understanding health problems, and that it can be humane.